add status_page role that deploys update-status.sh and its cron job.
script queries prometheus for caddy upstream health and writes
status.json + history to /srv/status/ every minute.
refs: PESO-94
Add firewall_alpine role for Alpine hosts with iptables persistence
and fail2ban SSH jails. Wire it into nuremberg-a's deploy stage.
Mail ports are already exposed via Docker port mappings in the
poste-io docker-compose — this captures the surrounding iptables
and fail2ban config that was previously undocumented.
Closes PESO-96
